EXPRESSION OF PORCINE CIRCOVIRUS CAPSID PROTEIN IN INSECT CELLS AND SELF-ASSEMBLED INTO VLPs

The capsid gene of PCV2b was cloned into the multiple cloning site of the pFastBacTMⅠvector of the Bac-to-Bac expression system under the control of PPH promotor.The recombinant plasmid rBacmid-cap was transformed into DH10Bac for bule/white selection and antibotics selection.The positive recombinant bacmid was transfected to Sf9 in logarithmic growth phase for harvesting recombinant Baculovirus.The expression protein in Sf9 which was infected by recombinant Baculovirus rvBac-cap was identified by IFA.HighFiveTM was infected by the rvBac-cap,and the culture supernatant was collected to detect the expression protein by Western blot and electron microscopy.The results showed that the recombinant protein was released into culture medium and self-assembled into PCV2-like particles(PCV2-VLPs) with a diameter of 17nm.The peak of protein expression was on the 5th day post infection.The efficient expression of PCV2-VLPs in cell culture could be a convenience for perotein purification and a basis for developing PCV2 genetically engineered vaccine.